1. Field of the Invention
The present invention relates to a joint adapter for a power drill screwdriver, and more particularly, to a joint adapter which can be used more easily and conveniently for a rapid exchange of the screw driver bits.
2. Description of the Prior Art
The joint adapter 10 for a (either electric or pneumatic) conventional power drill screw driver, as shown in FIG. 5, includes a driving shaft 12 with an insertion groove 11, a locating socket 14 with female thread 13, a washer 15 and an adjustable shell 17 with axial threaded internal hole 16. The driving shaft 12 is provided with male thread 18 within a certain range on which the locating socket 14 and the adjustable shell 17 are screwed one after the other. The washer 15 is interposed between the locating socket 14 and the adjustable shell 17 for strengthening the fixing effect and for avoidance of unexpected loosening.
In using, after the insertion piece 19 of the driving shaft 12 is inserted into a corresponding insertion groove of the power drill screw driver (not shown), the locating socket 14 and the adjustable shell 17 are screwed in the direction of the screw driver bit 20 for a certain distance. Meanwhile, a strong magnet 22 at the front end of the axial threaded internal hole 16 of the adjustable shell 17 approaches the screw driver bit 20 in order to attract the screw 24 in a stable state. Accordingly, the high speed screwing can be smoothly performed.
However, the above-mentioned joint adapter 10 has the following drawbacks:
1. The locating socket 14 and the adjustable shell 17 have to be respectively screwed to the expected positions due to the arrangement of the washer 15. Thus, the operational efficiency is greatly diminished.
2. As shown in FIG. 6, when the locating socket 14 and the adjustable shell 17 are screwed to the operation position of the screw 24, the screwing portion between the adjustable shell 17 and the driving shaft 12 is gradually reduced so that the adjustable shell 17 shakes or can become detached from the locating socket 14 and the driving shaft 12. Thus, difficulties in positioning and operation are experienced.
3. As shown in FIG. 7, in order to exchange the (slotted, Phillips, hexagonal and differently sized) screw driver bits 20, the locating socket 14 and the adjustable shell 17 have to be screwed to the bottom to let the screw drier bit 20 project more. Therefore, the operator can pull out the screw driver bit 20 more easily. After completing the exchange work, the operator has to screw the locating socket 14 and the adjustable shell 17 back to the operational position, thereby causing much inconvenience.
It is a primary object of the present invention to remove the above-mentioned drawbacks and to provide a joint adapter for a power drill screw driver which makes use of a sliding element and a resilient element to easily and rapidly complete the screwing work (including attaching the screw and exchanging a plurality of screw driver bits in a plurality of types and sizes) in order to enhance the operational efficiency and to meet the convenient and practical requirements.